• 한국수자원학회논문집
• /
• 제31권6호
• /
• pp.709-725
• /
• 1998

도시하천의 유출 및 수질특성을 홍제천 시험유역에서의 관측자료에 의하여 분석하였다. 시험유역의 수질은 건기시차집 관로에 의한 하수의 차단으로 비교적 양호한 수질을 보이는 반면, 이로 인하여 동기의 약 3-4개월동안에는 건천화의 현상을 보였다. 한편, 우기시에는 합류식 하수계통으로부터의 급격한 비점원 오염부하량의 증대를 보였다. 도시유출 및 수질을 해석하는 모형, SWMM, ILLUDAS, STORM, HEC-1 등을 적용하고 그 결과를 비교분석하였다. 또한, 시험유역에 대한 유출·수질상관식을 도출하고 그 적용성을 검토하였다. 검토 모형들은 전반적으로 양호한 적용성을 보였으며, 유출과 수질해석의 양면에서 SWMM이 검토모형중에서 가장 우수한 것으로 판단된다. 또한, 실측자료에 근거한 유출·수질상관 모형을 도출하였으며 우기시의 오탁부하량의 근사산정에 효과적인 것으로 판단되었으나, 유량이 관측 자료의 범위를 벗어나면 그 정확도가 크게 떨어졌다. 이 모형은 대상 유역의 관측자료 확충으로 보완되어 나가야 할 것이다. 한편 현재 실무에서 널리 사용되는 HEC-1도 도시유역에서 경제적으로 활용될 수 있을 것으로 판단된다.

• 한국환경과학회지
• /
• 제19권7호
• /
• pp.907-915
• /
• 2010

Agriculture nonpoint pollution source is a significant contributor to water quality degradation. To establish effective water quality control policy, environpolitics establishment person must be able to estimate nonpoint source loads to lakes and streams. To meet this need for orchard area, we investigated a real rainfall runoff phenomena about it. We developed nonpoint source runoff estimation models for vineyard area that has lots of fertilizer, compost specially between agricultural areas. Data used in nonpoint source estimation model gained from real measuring runoff loads and it surveyed for two years(2008-2009 year) about vineyard. Nonpoint source runoff loads estimation models were composed of using independent variables(rainfall, storm duration time(SDT), antecedent dry weather period(ADWP), total runoff depth(TRD), average storm intensity(ASI), average runoff intensity(ARI)). Rainfall, total runoff depth and average runoff intensity among six independent variables were specially high related to nonpoint source runoff loads such as BOD, COD, TN, TP, TOC and SS. The best regression model to predict nonpoint source runoff load was Model 6 and regression factor of all water quality items except for was $R^2=0.85$.

• 한국수자원학회논문집
• /
• 제47권11호
• /
• pp.1027-1037
• /
• 2014

본 연구에서는 하상변동 및 하상유지공 유실 문제가 발생했던 남한강과 금당천 합류부 지점을 대상으로 지류에서 유입되는 유량의 변화에 따른 흐름특성 및 하상변동 특성을 2차원 수치모형을 이용하여 분석하였다. 대상 구간의 수치모의 분석결과, 본류에서는 흐름집중 현상에 의해 지류 유입유량에 관계없이 합류 전에 비해 합류 후 유속이 더 큰 것으로 나타났다. 그러나 지류 유입유량이 클수록 지류하천의 하도 침식이 가속화되고 따라서 주하도가 형성되어 지류에서의 마름영역이 더 크게 나타났다. 이로 인한 지류에서의 하도 침식은 지류에서의 유사발생량을 증가시키고 침식된 유사는 합류부 구간에 퇴적되는 것으로 나타났다. 합류부 구간에서의 지류 유입부 퇴적은 본류 흐름을 좌안으로 집중시키고 좌안의 하상이 저하되는 현상을 야기하였다.

• Journal of Plant Biology
• /
• 제16권3_4호
• /
• pp.1-6
• /
• 1973

The distribution of plant communities along the Bukhan Riverside in Chun-seong was studied by means of the methods fo Curtis and Pattern. The communities were arranged in a single-dimensioned ordination on the basis of the importance values of the persistent species. Leading dominant species, form the 'low' level to the 'high' levels of the ordination gradient, were Phalaris arundinacea, Salix gilgiana, Artemisia feddei, Zoysia japonica, Pennisetum japonicum, and Arundinella hirta. These species from a continuum from the river to the dry grassland depending upon available soil-moisture. Standing crops in terms of dry weight and the nitrogen content of the above-ground parts of these species showed a good relationship with gradients of available soil-moisture.

• 한국농공학회지
• /
• 제33권4호
• /
• pp.84-95
• /
• 1991

The compaction ratio of the field dry density to the maximum dry density is generally adopted as the index of quality control for embankment of earthfill structures such as Earth Dam, Sea Dike, River Bank and Road. In case of coarse materials are included in the earth material, the compaction ratio will be varied in wide range since the dry density is influenced by quantity of coarse material in the soil. The treatment for the coarse material should be controlled carefully in testing. In this study, the compaction characteristics of the soil contained the coarse materials were researched and calibration of the suitability of field quality control methods were carried out. 28 Samples were made of clay(CL) and sandy soil (SM) mixed with gravel whose content were 0, 4, 6, 8, 10, 12, 15, 20, 25, 30, 35, 40, 45, and 60% in Weight. The compaction characteristics depending on the coarse material content were analysed through 4 types of compaction tests which are A-1, B-i, C-i and D-1. The adjusting coefficients for density and moisture content namely a and ${\beta}$ respectively were proposed in order to consider the effects depending on content of the coarse materials. The test methods to control reasonably and promptly the quality of earthfill were proposed after analysing the ranges of possible errors on the relative compaction ratio between laboratory compaction methods and field density testing methods.

• Ocean and Polar Research
• /
• 제25권1호
• /
• pp.75-87
• /
• 2003

The water balance calculation in the IRL shows that fresh groundwater discharge is the primary factor, with surface runoff from gaged and ungaged areas as the second freshwater contributor. Precipitation and evaporation are almost in balance fer the entire IRL. Due to high freshwater discharge from ground-water, the annual net flow is outward from the IRL to the continental shelf of the Atlantic Ocean resulting in a relatively short flushing time, denoted as $T_{0.5}$ (50% flushing time) and $T_{0.99}$ (99% flushing time). $T_{0.5}$, and. $T_{0.99}$ without a tidal effect in the Northern IRL are 17 and 114 days, respectively, during the dry season. During the wet season, they are 10 and 65 days, respectively. Tidal flushing effects are considered in central IRL due to the proximity to Sebastian Inlet. In the Northern Central zone during dry season, $T_{0.5}$, and. $T_{0.99}$ are 6 and 43 days, respectively and during the wet season 5 and 33 days. In the Southern Central zone they are 2 and 16 days for the dry season,2 and 15 days for the wet season. High groundwater seepage into the IRL is considered to be a positive effect in maintaining relatively good water quality condition even with few narrow inlets.

• 한국물환경학회지
• /
• 제36권6호
• /
• pp.521-534
• /
• 2020

In this study, the variation of water quality was analyzed for six sites in major tributaries of the Nakdong River Basin. Standard-FDC (Flow Duration Curve) was developed using PM (Percentile Method), one of the statistical FDC estimation methods. The LDC (Load Duration Curve) was obtained using the developed FDC. The current method and the LDC evaluation method were compared and analyzed to evaluate the achievement of TWQ (Target Water Quality). Regarding the monthly flow rate variation, the five sites showed the distribution of the lowest flow rate between May and June, indicating a high probability of dry weathering of the streams. The variation of water quality confirmed the vulnerable timing of flow rate in each site, and it is therefore deemed necessary to plan to reduce T-P and TOC. A comparison and evaluation of TWQ showed that there was a difference between the TWQ values achieved by the two techniques. In addition, the margin ratio to the 50% excess ratio can be found in the LDC evaluation. The results of the LDC evaluation by section and by month showed whether or not the water quality was exceeded by flow conditions, along with the vulnerable sections and timing. Accordingly, it is judged that this method can be used for water quality management in TMDLs (Total Maximum Daily Loads).

• 한국해양바이오학회지
• /
• 제2권2호
• /
• pp.120-122
• /
• 2007

A $Q_{10}$-producing photosynthetic bacterium was isolated from the silt at Nakdong river. The isolate had 1.55 mg of $Q_{10}$ per gram of dry cell. By the 16s-rDNA sequence analysis, the isolate was found to be Rhodobacter sphaeroids with 100% similarity (Genbank Accession No.=AM696701).

• 환경생물
• /
• 제26권3호
• /
• pp.233-239
• /
• 2008

본 연구는 한강하류역에서 2개 정점을 선정하여 2004년 2월부터 2005년 2월까지 갈수기에 격주 간격으로 인공기질을 이용하여 부착돌말류에 의한 수질평가를 수행하였다. 조사기간 중 출현한 부착돌말류는 총 60분류군으로 2목 3아목 8과 18속 51종 7변종 2품종으로 구성되어 있었다. 정점별 우점종은 정점 1에서 광적응성 종인 A. granulata (22.76$\sim$30.30%), M. varians (17.44$\sim$34.78%)와 호오염성 종인 N. palea (15.00$\sim$31.76%)등이 출현하였으며, 정점 2에서는 호오염성 종인 N. palea (19.86$\sim$58.20%)가 주요 우점종이 었다. DAIpo지수는 정점 1에서는 평균 40.6을, 정점 2에서는 평균 32.1로 각각 $\beta$-중부수성 수역이었으나, 정점 2에서 수질이 더 악화되어 있었다. 본 연구에서 출현한 우점종들이 한강하류역에서 수질 판정할 수 있는 주요 지표종이며, 이들의 상대빈도에 의한 DAIpo지수는 수질평가의 유용한 수단이 될 수 있었다.

• 한국환경생태학회:학술대회논문집
• /
• 한국환경생태학회 2003년도 추계학술논문발표회 논문집
• /
• pp.105-126
• /
• 2003

In Korea most of annual rainfall is concentrated in several episodic heavy rains during the season of summer monsoon and typhoon. Because of uneven rainfall distribution many dams have been constructed in order to secure water supply in dry seasons. The Han River system has the most dams among Korean rivers, and the river is a series of dams now. Reservoirs need different strategy of water quality control from river water. Autochthonous organic matter and phosphorus should be the major target to be controlled in lakes. In this Paper some problems are discussed that makes efforts of water quality improvement ineffective in lakes of Korea, even after the substantial investment to wastewater treatment facilities.1) Phosphorus is the key factor controlling eutrophication of lakes and the reduction ofphosphors should be the major target of water treatment. However, water quality management strategy in Korea is still stream-oriented, and focused on BOD removal from sewage. Phosphorus removal efficiency remains as low as 10-30%, because biological treatment is adopted for both secondary treatment and advanced treatment. The standard for TP concentration of the sewage treatment plant effluent is 6 mgP/l in most of regions, and 2 mg/l in enforced region near metropolitan water intake point. TP in the effluents of sewage treatment plants are usually 1-2 mg/1, and most of plants meet the effluent regulation without a further phosphorus removal process. The generous TP standard for effluents discourages further efforts to improve phosphorus removal efficiency of sewage treatment. Considering that TP standard for the effluent is below 0.1 mg/l in some countries, it should be amended to below 0.1 mg/l in Korea, especially in the watershed of large lakes.2) Urban runoff and combined sewer overflow are not treated, even though their total loading into lakes can be comparable to municipal sewage discharges on dry days. Chemical coagulation and rapid settling might be the solution to urban runoff in regard of intermittent operation on only rainy days.3) Aggregated precipitation in Korea that is concentrated on several episodic heavyrains per year causes a large amount of nonpoint source pollution loading into lakes. It makes the treatment of nonpoint source discharge by methods of other countries of even rain pattern, such as retention pond or artificial wetland, impractical in Korea.4) The application rate of fertilizers in Korea is ten times as high as the average ofOECD countries. The total manure discharge from animal farming is thought to be over the capacity of soil treatment in Korea. Even though large portion of manure is composted for organic fertilizer, a lot of nutrients and organic matter emanates from organic compost. The reduction of application rate and discharge rate of phosphorus from agricultural fields should be encouraged by incentives and regulations.5) There is a lot of vegetable fields with high slopes in the upstream region of the HanRiver. Soil erosion is severe due to high slopes, and fertilizer is discharged in the form of adsorbed phosphorus on clay surface. The reduction of soil erosion in the upland area should be the major preventive policy for eutrophication. Uplands of high slope must be recovered to forest, and eroded gullies should be reformed into grass-buffered natural streams which are wider and resistant to bank erosion.